The 4-OH-L-praline and L-proline have been studied in water + alcohol (EtOH, 1-PrOH and 2-PrOH) mixtures at T= 298.15 I< by calorimetry. The dissolution enthalpies of 4-OH-L-proline and L-proline have been determined. The standard values of dissolution enthalpies (Delta H-sol(center dot)) and transfer enthalpies (Delta H-tr(center dot)) of 4-OHL-proline and L-proline from water to (H2O + EtOH), (H2O + 1-PrOH) and (H2O + 2-PrOH) mixtures are calculated. According to the McMillan-Mayer's theory, the corresponding heterogeneous enthalpic coefficients of pairwise interaction (hxy) of 4-OH-L-proline and L-proline with the alcohols molecules have been calculated. It has been found that these coefficients become increasingly positive in EtOH, 1-PrOH and 2-PrOH sequence. A comparative analysis of the enthalpic characteristics of 4-OH-L-proline and L-proline dissolution in the mixtures studied has been made. The effect of substitution of H by OH group in 4-OHL-proline has also been studied and discussed.
